Healthcare service redesign and improvement has become an important activity that health system leaders and clinicians realise must be nurtured and mastered, if the capacity issues that constrain healthcare delivery are to be solved. However, little is known about the critical success factors that are essential for sustaining and scaling up improvement initiatives. This situation limits the impact of these initiatives and undermines the general standing of redesign and improvement activity within healthcare systems. The conduct of the doctoral research detailed in this study protocol will be nested within a broader parent study that seeks to address this problem by drawing on the theory of 'institutional entrepreneurship'. The doctoral research will apply this idea to understanding the capacities and capabilities required at the organisation level to bring about transformational change in healthcare services.The parent study is predominantly qualitative, is multilevel in nature and has been codesigned with five partner healthcare organisations. The focus is a sector-wide attempt in an Australian state jurisdiction to transfer new redesign and improvement knowledge into the public healthcare system. The doctoral research will focus on the implementation of the sector-wide approach in one healthcare service in the jurisdiction. This research involves interviews with project team members and stakeholders involved in two improvement initiatives undertaken by the health service. It will involve interviews with redesign and improvement leaders and senior managers responsible for the overall health service improvement approach. The methods will also include immersive fieldwork, interviews and focus groups. Appropriate methods for coding and thematic extraction will be applied to the qualitative data.Ethical approval has been granted by the health service and Monash University Human Research Ethics Committee. Dissemination will be facilitated via academic publication, industry reports and workshops and dissemination events as part of the broader project.